I'm having this idea to create a midi controller that works with Resolume Arena 4.For you guys that don't know resolume, its a VJ program, you can see it as a mixing software for video clips

I did some thinking and first off all I'm going to have a lot of analog and digital components to give you guy's a list:

28 x Pot-meter (analog in)

3x Red LED (analog out)

3x Green LED (analog out)

5x Slide Pot-meter (analog in)

48 x Push buttons (digital in)

48 x R LEDs (indiactors) (digital out)

I draw something very quickly in photoshop so you can see where all the components come

Now my questions are:

whats the best board I use for this (a cheap as possible solution in general please) and is there some thinks I need to watch on like example external power supply for all the LEDs, extra ICs for port expansion etc.

not to forget: I want this build to be work with midi and it has to be midi over USB,(no Serial to MIDI conversion)the VJ software takes a lot of resources so I don't want to waste any more cpu time on serial to MIDI conversion

It looks like you are trying to make a "Control Surface" (example). But, MIDI is digital (until you get to the instrument that's generating sounds), and you've got lots of analog ins & outs. Is this analog audio, video, or what?

I never built anything with MIDI, and if it was me I'd start by experimenting with something smaller... Maybe build & test one of your functions or "modules" at a time before trying to put everything together in a big project like that.

if you use a arduino that is based on Atmel ATmega32U4 this chip could be your USB Midi thing.there are some finished libs for Mouse and Keyboard - but as far as i know no lib for Midi - one option is to check LUFA (there are midi examples)but i dont know if it is possible to get this in combination with the normal Arduino IDE...